Heat exchanger apparatuses nowadays play an increasingly important role in many fields of engineering, in particular automotive engineering, in power plants and in environmental engineering. The components of heat exchanger apparatuses of this type are usually connected or joined to one another by means of welding or soldering.
The joining by means of soldering often takes place using what is known as a nickel solder (Ni solder). A nickel solder of this type is distinguished by a high resistance to oxidation and corrosion, but has the drawbacks compared to other solders, such as for example copper solders (Cu solder) that the soldering gap usually has to be at least narrower than 0.1 mm in order to prevent the formation of precipitation products in the soldered seam, which reduce the strength and/or increase the corrosion, that all Ni solders are relatively expensive and that to avoid oxidation of the solder surface, the soldering process is usually carried out in a vacuum soldering furnace, which means that the mass production of nickel-soldered heat exchangers of this type, on account of the process times required in a vacuum soldering furnace, is relatively complex and therefore also expensive.
However, the use of Cu-soldered heat exchanger apparatuses represents a problem in many fields, since Cu solder at times does not have the required resistance to corrosion or oxidation in particular when exposed to the fluids flowing through the heat exchanger apparatus, and consequently it may be damaged at the joint seams, in particular as a result of corrosion or oxidation.